Spinnerette lubricant



' due to evaporation of the solvent.

Patented Feb. 17, 1942 George D. Graves and Warner J. Merrill,Wilmington, Del., assignors to E. I. du Pont de Nemours & Company,Wilmington, DeL, a corporation of Delaware No Drawing. Application March24, 1939, Serial No. 264,038

, stance which will prevent the fiber-forming com- Claims.

This invention relates to improvements in the to the use of spinnerettelubricants in spinning.

Artificial fibers are in general prepared by two methods: (1) by wetspinning which consists in extruding a solution of the fiber-formingmaterial through small orifices, i. e., through a spinnerette, into aliquid which precipitates the fiber-forming material, and (2) by dryspinning which consists in passing a solution of the fiberformingmaterial through a spinnerette into a heated chamber whereupon filamentsare formed method, which has thus far found little application but whichmay be successfully practiced by means of the invention disclosedherein, consists in extruding the molten fiber-forming material througha spinnerette.

In dry spinning difficulty is sometimes encountered in starting and inmaintaining smooth spinning performance because the solution tends toflow along the surface of the spinnerette and fall off in drops insteadof in a uniform steady flow. Various methods for overcoming thisdifficulty have been used, including the application of a film of liquid(solvent or non-solvent) to the spinnerette surface prior to spinning.The

A third preparation of artificial fibers, and particularly 1 thespinneret surface, prevent the fiber-forming liquids which have beensuggested for this purpose are low molecular weight substances, such asbenzene and toluene. Substances applied to the spinnerette to facilitatespinning are herein referred to as spinnerette lubricants. In wetspinning fouling of the spinnerette is seldom encountered unless thespinnerette is placed outside the coagulating bath. In melt spinning,however, this difl'iculty is particularly acute since no solvent is usedand the spinning is conducted at an elevated temperature. In meltspinning the fiber-forming material has a pronounced tendency to adhereto or cake on the surface of the spinnerette and thus prevent smoothspinning. Application of the solvents or non-solvents recommended forovercoming this difficulty in the case of dry spinning is of limitedutility in melt spinning due to the fact that these agents decompose orvolatilize readily and therefore are removed from the spinnerettesurface at the temperatures used in this process. No satisfactory agentsor lubricants have been suggested for use in this connection.

This invention has as an object improvements in the spinning ofartificial fibers. A further object is to prevent the fouling ofspinnerette orifices during the spinning of artificial fibers. A furtherobject is to coat spinnerettes with a subposition from adhering to thesurface thereof. A still further object is to coat the spinnerette witha non-volatile, stable, inert composition which will adhere to thespinnerette surface even at elevated temperatures such as those used inmelt spinning. Other objects will appear hereinafter.

These objects are accomplished by coating the spinnerette surface orface with a thin film of a polymerized hydrocarbon.

The disadvantages referred to above are overcome in whole or in part bythe use of polymerized hydrocarbons which we have found to beparticularly effective as spinnerette lubricants. These products are ingeneral non-solvents for the fiber-forming material and appear toincrease the surface tension of the fiberforming material to a greaterextent than do previously described non-solvents. They are non-volatile,heat stableand, when applied to material from adhering thereto. Theselubricants are especially useful when the spinning operation isconducted at elevated temperatures as in melt spinning.

. The term polymerized hydrocarbon is used to designate polymers derivedfrom the polymerization (with or without subsequent hydrogenation) ofunsaturated hydrocarbons, such as ethylene, propylene, isobutylene,butadiene, isoprene, styrene, cyclopentadiene, indene, cumaron,unsaturated petroleum products, etc., as well as polymeric hydrocarbonsderived from the condensation polymerization of monomeric hydrocarbonderivatives, such as benzyl chloride. These products range in propertiesfrom viscous oils to resins or rubber-like materials. They arenonvolatile and stable even at temperatures as high as 300 C. Especiallyuseful spinnerette lubricants of this class are polymerized olefins,polymerized cracked gasolines, meta-styrene (polymerized styrene),polyphenyl's, plasticized rubber, and hydrogenated rubber. Of this grouppolymerized isobutylene of molecular weight ranging from 2,000 to100,000 is especially useful. This product may be prepared among othermethods by polymerizing isobutylene in the presence of a halide of apolyvalent metal, such as aluminum chloride, stannic chloride, or borontrifiuoride. The product is a soft, semi-rubberlike material, soluble inaliphatic and aromatic hydrocarbons. Polymeric hydrocarbon products soldas Vistanex (trade-mark Serial No. 369,113, November, 26, 1935) andViskanol such, or in the form of a solution in a suitable solventtherefor, such as benzene or toluene. The lubricant is preferablyapplied to both the inside and outside of the spinnerette. Commonprocedure consists in wiping the face and inside of the spinneret with acloth or sponge soaked with the lubricant or solution of lubricant. Thisis preferably done immediately prior to spinning.

As already indicated, application of the polymerized hydrocarbon to thesurface of the spinnerette greatly facilitates the spinning of thefiber-forming material, particularly when the spinning operation iscarried out at elevated temperatures. The properties of the spinnerettelubricants described herein make them particularly valuable in the meltspinning of fiber-forming linear polymers and especially the so-calledfiber-forming linear condensation polymers. By the term fiber-forminglinear condensation polymers is meant fiber-forming linear polymerswhich are obtainable by the process of condensation described in the U.S. Patent No. 2,071,250 of W. H. Carothers and in Carothers & -Hill, J.Am. Chem. Soc. 54, 1559 (1932). Fiber-forming linear polymers, althoughobtainable by a condensation process, may be in some instancesobtainable by other processes and therefore the term condensation ismeant to include compounds of the type disclosed hereinafter whether ornot such compounds are produced by chemical combination, condensation,or by some other process. Fiber-forming linear condensation polymers aretough, opaque solids which exhibit sharp X-ray powder diffractionpatterns (indicating crystallinity) and have definite melting points.These fiber-forming polymers will be referred to as superpolymers. Thus,the term "superpolyamide will signify a polyamide capable of yieldinguseful and pliable fibers. Linear superpolymers in general melt withoutdecomposition which means that they can be spun from melt without theaddition of a solvent.- The temperature at which the polymer is spunwill of course depend upon its melting point. The most usefulsuperpolymers from the standpoint of fiber qualities are thesuperpolyamides, i. e.,

products obtainable by the polymerization of amino acids or theiramide-forming derivatives including caprolactam or from the reaction ofsuitable diamines with dicarboxylic acids or amide-forming derivativesof dibasic carboxylic acids. This latter class of compounds is morefully described in Carothers U. S. Patent No. 2,130,948. high meltingpoints, insolubility in most organic solvents and excellentfiber-forming qualities. The most useful for the preparation of textilefibers are those having a'melting point above 220 C. In order to meltspin these high melting products, it is necessary to use a spinnerettelubricant which is non-volatile even at high temperatures, is stable,adheres well to the spinnerette surface, and prevents the fiber-formingmaterial from wetting the surface of the spinnerette. The followingexamples are illustrative of the methods used in carrying out ourinvention:

Example I A metal spinnerette having ten orifices, each having adiameter of 0.0078 inch, placed at the bottom of 0.0125 inch cone-shapedprotrusions These products are characterized by aacaese and acetyienicunsaturation and in which R extending downward from the face of thespinnerette, was coated inside and outside with a kerosene solution ofpolymerized isobutylene having a molecular weight of approximately14,000. Through this spinnerette was then spun at a temperature of 280to 290 C. under a pressure of 50 lb./sq. in. applied with oxygen-freenitrogen, parts by weight of polyhexamethylene adipamide, a linearsuperpolyamide derived from the reaction of hexamethylene diamine withadipic acid. The filaments which came from the spinnerette were wrappedaround one or more times on a motor driven drum having a peripheralspeed of 304 ftJmin. and then collected on a second drum having aperipheral speed of 600 ft./min. The. extent of stretching orcold-drawing thus produced was Spinning proceeded smoothly from start tofinish without any interruptions until the entire charge had been spun.This required 45 minutes. The resultant oriented fibers were unusuallystrong (tenacity 5.2 grams per denier based on the denier at break) andhad excellent elastic properties.

Coating of the spinnerette with a liquid such as toluene, benzene, orthe like had little beneficial effect, since these liquids volatilizedalmost immediately at the high temperature used in this spinningoperation.

Example II A melt of cellulose acetate composition consisting of 66.7%celluloseiacetate and 33.3% dimethoxyethyl phthalate was spun at atemperature of 200 to 205 C; at 100 lb./sq. in. through a. two-orifice(0.0091 inch diameter) staple spinnerette, the face of which had beencoated with a thin film of polymerized isobutylene. No diffiin the meltsuperpolyamides. The most useful polymers of this type are thoseobtainable from the reaction of suitable diamines of formulaNH2CH2RCH2'NH2 and dicarboxylic acids of formula HOOCCHeR'CHzCOOH ortheir amideforming derivatives (i. e., the ester anhydride, amide, oracid chloride) in which R and R are divalent hydrocarbon radicals freefrom olefinic has is (CH2)' wherein a: and y are integers and .r is atleast two. As examples falling within one or both of these classes mightsebacamide,

- ylene adipamide, polyp-xylylene sebacamide and.

Although the use of polymerized hydrocarbons from which the spinneretteis made.

as a spinnerette lubricant in the melt spinning of linear superpolymersof the kind mentioned in Example I and described in the applicationpreviously referred to has been emphasized, these lubricants are broadlyapplicable in the spinning art. They can, for example, be used in thespinning of various cellulosic materials, particularly cellulose estersand ethers, vinyl resins, etc. The polymerized hydrocarbons can be usedalone, in admixture, or in conjunction with other materials, such as lowboiling solvents therefor. If the spinning operation is being carriedout at ordinary temperatures, it is generally desirable to dilute thepolymerized hydrocarbon with a solvent which will reduce its viscosity.In most cases it is not necessary to coat both the inside and outside ofthe spinnerette; coating of the outside or face of the spinnerette isusually sufiicient. The spinnerette lubricants of this invention areapplicable regardless of the material For example, the lubricants can beused to advantage in the spinning of superpolyamides from spinnerettesconstructed of or lined with silver, gold, tantalum, platinum andVarious alloys.

It will be seen from the foregoing description that we have disclosednew spinnerette lubricants which possess to a high degree the propertiesmost desired in materials of this kind. The heat stability andnon-volatility of these lubricants to be understood make themparticularly valuable in the manufacture of artificial fibers byprocesses which require that the spinning operation be carried out atelevated temperatures. v

As manyapparently widely diiterentembodiments of this invention may bemade without departing from the spirit and scope thereof, it is that wedo not limit ourselves to the specific embodiments thereof except asdefined inthe appended claims. 1

We claim:

1. The process of improving the spinning property of a filament-formingspinnerette which comprises coating the same with a lubricant to preventfouling of the spinnerette orifices, said lubricant composed of apolymer of an unsaturated hydrocarbon material.

2. The process of improving the spinning property of a filament-formingspinnerette which comprises coating the same with a. lubricant toprevent fouling of the spinnerette orifices, said lubricant composed ofa polymer of isobutylene.

3. The process of improving the spinning property of a filament-formingspinnerette which comprises coating the same with a lubricant to preventfouling of the spinnerette orifices, said lubricant composed ofmetastyrene.

4. The process of improving the spinning property of a filament-formingspinnerette which comprises coating the same with a solution of alubricant to prevent fouling of the spinnerette orifices, said lubricantcomposed of apolymer of an unsaturated hydrocarbon material.

5. The process of improving the spinning property of a filament-formingspinnerette which comprises coating the inner and outer surfaces of saidspinnerette with a lubricant to prevent fouling of the spinneretteorifices, said lubricant composed of a polymer of an unsaturatedhydrocarbon material.

' GEORGE D. GRAVES.

WARNER J. MERRILL.

